Effects of pyric herbivory on prairie-chicken (Tympanuchus spp) habitat

Abstract

The reduction and simplification of grasslands has led to the decline of numerous species of grassland fauna, particularly grassland-obligate birds. Prairie-chickens (Tympanuchus spp.) are an example of obligate grassland birds that have declined throughout most of their distribution and are species of conservation concern. Pyric herbivory has been suggested as a land management strategy for enhancing prairie-chicken habitat and stabilizing declining population trends. We assessed differences in vegetation structure created by pyric herbivory compared to fire-only treatments to determine whether pyric herbivory increased habitat heterogeneity for prairie-chickens, spatially or temporally. Our study was performed at four sites in the southern Great Plains, all within the current or historic distribution of either lesser (T. pallidicinctus), greater (T. cupido), or Attwater's (T. cupido attwateri) prairie-chickens. Key vegetation characteristics of grass cover and vegetation height in pyric herbivory and fire-only treatments were within the recommended range of values for prairie-chickens during their distinct life history stages. However, patches managed via pyric herbivory provided approximately 5% more forb cover than fire-only treatments for almost 30 months post-fire. Additionally, pyric herbivory extended the length of time bare ground was present after fires. Pyric herbivory also reduced vegetation height and biomass, with mean vegetation height in pyric herbivory treatments lagging behind fire-only treatments by approximately 15 months. Canopy cover in fire-only treatments exceeded levels recommended for prairie-chicken young within 12 months post-fire. However, canopy cover in pyric herbivory treatments never exceeded the maximum recommended levels. Overall, it appears that pyric herbivory improves vegetation characteristics reported as critical to prairie-chicken reproduction. Based on our results, we suggest pyric herbivory as a viable management technique to promote prairie-chicken habitat in the southern Great Plains, while still accommodating livestock production.

Pyric herbivory in a temperate European wood‐pasture system

“…Patch‐burn grazing has been suggested as a way to incorporate pyric herbivory in grazing management regimes (Fuhlendorf & Engle, 2001, 2004), as a form of rotational grazing without fencing. Patch‐burn management can increase heterogeneity in vegetation structure (Leis et al., 2013; McGranahan & Kirkman, 2013; Starns et al., 2020) and also the variability in functional groups in plants (McGranahan et al., 2012). Until now, the common idea of conservation management practices has been to allow an intermediate level of grazing, which is often applied to entire areas creating uniform and homogenised ecosystems (Briske et al., 2003; Fuhlendorf & Engle, 2001).…”

“…Since then, the term has been used frequently, mostly in studies from North America (e.g. see Allred et al, 2011;Lautenbach et al, 2021;Leverkus et al, 2018;Starns et al, 2020), Australia (Reid et al, 2023) and Africa (Archibald, 2008;Archibald & Hempson, 2016;Donaldson et al, 2018;Eby et al, 2014;Krook et al, 2007). These studies suggest that pyric herbivory creates heterogeneity on much broader scales than when fire and herbivory act as two separate forces (see also Fuhlendorf et al, 2009).…”

Spot-fire distance increases disproportionately for wildfires compared to prescribed fires as grasslands transition to Juniperus woodlands

“…Prescribed fires can prevent and reverse woody encroachment to mitigate wildfire risk [ 11 , 23 , 46 ]. In addition, prescribed fires can boost forage production [ 83 ], enhance grassland biodiversity and wildlife habitat [ 84 – 86 ], and control invasive species [ 87 , 88 ]. Our results provide an additional level of scientific support for the application of prescribed fire in grassland systems that can be used to support policy and management that promote pro-active prescribed fire application.…”

Wild herbivores and cattle have differing effects on postfire herbaceous vegetation recovery in an African savanna

“…Informed by the long history of fire and grazing in African savannas (Anderson, 2006; Milchunas et al, 1988; Van Langevelde et al, 2003), fire and herbivory prescriptions have become important management interventions in these systems (Odadi et al, 2017; Trollope, 2011). As a result, both the separate and interactive effects of fire and herbivory have been extensively studied (e.g., Allred et al, 2011; Anderson, 2006; Bodí et al, 2014; Charles et al, 2017; Eby et al, 2014; Edwards et al, 2010; Fuhlendorf et al, 2009; Laclau et al, 2002; Porensky, Bucher, et al, 2013; Scheiter et al, 2012; Starns et al, 2020; Van Coller et al, 2018).…”

“…In addition, these drivers often interact with each other through complex feedback loops to influence vegetation dynamics (Collins & Calabrese, 2012; Holdo et al, 2009; Midgley et al, 2010; Novellie & Kraaij, 2010; Starns et al, 2020). For example, the high‐quality regrowth and reduced cover in previously burned areas attract herbivores (pyric herbivory) due to improved pasture quality and reduced perceived predation risk (Eby et al, 2014; Kimuyu et al, 2017; Riginos & Grace, 2008; Sensenig et al, 2010).…”